class_docstr: CelebA-HQ dataset, downsampled as 256x256.
code: def preprocess_example(self, example, mode, hparams):
      del mode, hparams  # unused
      example["inputs"].set_shape((256, 256, 3))
      return example
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import image_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import metrics
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 2 for calling the ImageCelebahq256 obj's underlying member method code with example usage: obj.preprocess_example(example, mode, hparams) and returns: example